Various air bag restraint systems have been proposed in which an access door is arranged behind a continuously formed outer skin or cover. In some cases the underside of the outer skin is perforated or weakened. In such arrangements as shown in U.S. Pat. Nos. 3,622,176 and 4,246,213 the weakened sections represent underlying depressions in the outer cover which show as an outline of an access door for an underlying air bag assembly. Furthermore, such systems require that the outer cover be torn apart at the weakened seams. If the seams are irregular in form the opening force will vary and at times may tend to impede the release of an air bag.
In other arrangements, the cover assembly includes a separate cutting device that will pierce the outer skin. Examples of such separate cutting devices are set forth in U.S. Pat. No. 4,097,064 and copending U.S. application Ser. No. 601,406 filed Oct. 22, 1990 now U.S. Pat. No. 5,035,444.